What Is an inventory management system? Functions and benefits at a glance

Key takeaways 

• An inventory management system (in German: Warenwirtschaftssystem or WWS/WaWi) runs purchasing, warehousing, and sales centrally in one piece of software, without paper trails, Excel sheets, or a stack of separate tools
• The core functions are purchasing, warehouse management, order processing, goods receipt, and stocktaking, usually with connections to shop systems, point of sale, and accounting
• An inventory management system pays off for commerce businesses from around 50–100 orders per day, or as soon as Excel and manual processes start creating errors, overselling, or wasted time
• The most important difference from an ERP: a inventory management system only covers the flow of goods, an ERP system also covers accounting, CRM, production, and controlling
• Cloud-based systems start at under €100 per month, integrated solutions for growing SMBs run in the mid three-figure to four-figure range

What is an inventory management system?  

Structured processes let you optimize the flow of goods. Efficient handling of goods, documenting inventory and movement data, and running goods movements with intent are what make commerce operations efficient. You always know where your goods are, how often each item has sold, and which items get returned most often.

What does an inventory management system do? 

An inventory management system makes sure the right goods are in the right place, in the right quantity, at every moment. It supports every step of the process, from purchasing through warehousing to goods dispatch.

An inventory management software gives you visibility into the full flow of goods through your business and helps you plan, manage, and run it. What makes that possible are defined processes that can run automatically, independent of the specific person on shift. Instead of a loose paper trail, every step is captured digitally by the system.

Beyond the general benefits, a inventory management system supports specific departments in their day-to-day work:

Pros and cons of an inventory management system 

An inventory management system brings real benefits. Replacing complicated Excel setups, awkward workarounds, and manual processes will give your business back real time and a much better overview.

That said, using an inventory management system also comes with a few downsides. Especially if you're thinking about long-term company growth, an inventory management system on its own isn't always the ideal fit.

Inventory management, as the name suggests, only covers one part of the business. It's not a full-scope business software that supports planning, managing, and running all your resources. The risk is that you end up with an inventory management system as an island solution that you then have to bolt other software onto.

What you end up with is a patchwork of point solutions for different areas like materials management, accounting, and customer management. On top of that, some industries (grocery retail is a good example) have strict requirements around expiration dates and batch tracing that a pure inventory management system may not cover.

Functions of an inventory management system 

Purchasing 

The system runs the full procurement process: demand planning, automatic purchase suggestions when items hit their minimum stock level, supplier inquiries, order placement by email or EDI, and invoice verification. All communication, prices, and lead times sit in one place. No hunting through spreadsheets, no manual matching.

Warehouse management

Warehouse management is the heart of any inventory management system. You can see at any moment which items are in stock, in what quantity, and at what location, including variants like colors or sizes. The system distinguishes between actual and available stock (open orders already factored in) and optimizes picking routes, storage locations, and multi-stage processes.

Sales and order processing

From quote through order confirmation, shipping, invoicing, accounts receivable, and returns: the system automates every step. Orders from the shop, marketplaces, or B2B inquiries flow into one place. The system automatically generates shipping labels, delivery notes, and invoices, and triggers returns management.

Stocktaking

For companies with statutory reporting requirements, stocktaking is required by law. An inventory management system supports full-date, perpetual, and annual stocktakes through mobile data capture via scanner or smartphone app, instead of manual count sheets. During evaluation, the system corrects any discrepancies automatically and values the goods correctly for the balance sheet.

POS integration

For brick-and-mortar retail, the inventory management system has to communicate seamlessly with the point of sale. Every sale at the counter updates central inventory immediately. That's the prerequisite for real omnichannel commerce without data gaps between store, online shop, and marketplace.

Integration with accounting

Pure inventory management systems usually connect to external accounting tools or tax advisors through DATEV export (Germany-specific). Integrated solutions like an ERP have accounting built in, including automatic transfer of invoices, payments, and credit notes. On top of that, the inventory management system delivers reports and KPIs for faster, better decisions.

At what company size does an inventory management system make sense? 

A few years ago, inventory management systems were complex IT projects that would quickly overwhelm small businesses both financially and operationally.

Thanks to easy cloud software, even small businesses can now benefit from an inventory management system. If you're already noticing that Excel setups and manual processes are creating errors and long process times, it's worth thinking about inventory management software.

What does an inventory management system cost? 

The cost of an inventory management system varies significantly. A blanket answer is hard to give. Key factors that drive cost include:

• Deployment model (on-premise or cloud)
• Pricing model (subscription or license purchase)
• Company size
• Company requirements

Beyond the software itself, you may need to budget for additional purchases like POS systems, receipt printers, or barcode scanners. Depending on the software, there can also be operating and maintenance costs. Total cost of ownership (TCO) can therefore run higher than the sticker price.

What types of inventory management systems exist? 

1. Closed systems 

Closed inventory management systems cover every function (purchasing, sales, production, warehousing) inside a single system. A closed system typically has no interfaces to other systems and works as a stand-alone solution.

2. Open systems 

An open inventory management system covers the most important functions, like goods receipt and dispatch. Additional functions are added through interfaces to other software. Things like ordering and invoicing can be plugged in via those interfaces.

3. Integrated systems 

An integrated inventory management system, like a closed system, covers every necessary function in one piece of software. On top of that, additional interfaces to external services like shop systems, suppliers, or banks are available. This is how data gets shared with third parties and communication with external partners stays connected.

ERP system vs. inventory management system: what's the difference?  

An inventory management system covers purchasing, warehousing, and sales. An ERP system additionally covers accounting, production, CRM, HR, and controlling, meaning the whole company instead of just the flow of goods. For pure commerce businesses up to around 10 employees, a inventory management system is often enough. As soon as multiple sales channels, accounting, and CRM come into play, an ERP is the better fit.

👉 Full comparison with a comparison table: inventory management vs. ERP

6 tips for efficient inventory management 

1. Define product and item categories: Set up a hierarchy for your products and items so you have a clear overview. For example, you might have a product group like "men's outerwear" and beneath that item groups like "t-shirts" and "shirts." This helps later when you're analyzing performance.
2. Set up a standardized process: Standardizing your flow of goods helps you eliminate typical error sources up front and make workflows efficient. Write clear process descriptions and define responsibilities across the team.
3. Optimize your inventory levels: An inventory management system lets you run detailed analyses of well-performing versus poorly performing items. Bestseller/slow-mover lists let you cut dead stock and keep enough of the top sellers on hand.
4. Build a stocktaking plan: Stocktaking is an important part of the annual close. The physical count can be time-consuming and stressful. An inventory management system with a stocktaking module, plus a sensible plan, keeps the effort under control.
5. Run spot checks: Depending on what you sell, shrinkage or theft can be a problem. Running occasional spot checks in the warehouse helps you catch unusual inventory changes early. It also helps with the annual stocktake.
6. Integrate other departments: For maximum process efficiency, integrating other areas like a CRM for customer data or a connection to a fulfillment provider matters. An ERP system can help you run the business end-to-end.